package features.advance.leetcode.tree.easy;

import features.advance.leetcode.tree.model.TreeNode;
import features.advance.leetcode.util.TreeUtil;

/**
 * @author LIN
 * @date 2022-08-03 12:03
 *
 *
 *  226. 翻转二叉树
 *
 *  难度：简单
 *
 * 给你一棵二叉树的根节点 root ，翻转这棵二叉树，并返回其根节点。
 *
 *
 * 示例 1：
 *
 *
 *
 * 输入：root = [4,2,7,1,3,6,9]
 * 输出：[4,7,2,9,6,3,1]
 * 示例 2：
 *
 *
 *
 * 输入：root = [2,1,3]
 * 输出：[2,3,1]
 * 示例 3：
 *
 * 输入：root = []
 * 输出：[]
 *
 *
 * 提示：
 *
 * 树中节点数目范围在 [0, 100] 内
 * -100 <= Node.val <= 100
 */
public class Solution226 {

    public static void main(String[] args) {
        Solution solution = new Solution() {
        };
        TreeNode root = TreeUtil.stringToTreeNode("[4,2,7,1,3,6,9]");
        TreeNode invertTree = solution.invertTree(root);
        System.out.println(invertTree);
    }

    static class Solution {
        public TreeNode invertTree(TreeNode root) {
            if(root == null){
                return null;
            }
            invertTree(root.left);
            invertTree(root.right);
            TreeNode t = root.right;
            root.right = root.left;
            root.left = t;
            return root;
        }
    }
}
